IgM antibody specific for 2'-3' cyclic nucleotide phosphodiesterase I (CNPI), a protein enriched in oligodendrocytes and myelin membranes, is found in the cerebrospinal fluid and serum of 75 percent of patients with multiple sclerosis (MS). This project will explore the response to CNPI as a unique marker and specific probe for persistent viral infection in MS. The project will test the hypothesis that epitopes on CNP1 are structurally related to nucleotidyl moieties on herpes virus proteins. The specific aims of the project are to (1) isolate CNPI epitopes and confirm CNPI modification, (2) examine anti-CNPI IgM from MS sera for reactivity with known herpes virus proteins, and (3) use anti-CNPI IgM to isolate viral proteins from the brain of MS patients.